Girt construction for compression-type derricks



May 27, 1930.

C. W. LYNCH GIRT CONSTRUCTION FOR COMPRESS'ION TYPE DERRICKS Filed Aug. 18, 1926 7/ 5 ll/Qf/Illlfl INVEN TOR. C. Wglyizcfz; BY-

A TTORNEYS.

Patented May 27, 1930 UNITED STA EFEE attain en rant cri ics CHARLES W. LYNCH, OF PERRY, OKLAHOMA, ASSIGNOR- 1'0 PICKEBJING LUMBER COM.- IPANY, OF KANSAS CITY, MISSOURI, A CORPOBATION OF DELAWARE GIRT CONSTRUCTION FOB COIEPEESSION-TYPE DERRICKS Application filed August 18, 1926. Serial No. 129,8?6.

This invention relates to wood derricks of the compression or crossed-brace type, and has for its object to provide for the use of the relatively light girts without any sacrifice of strength necessary to resist high winds and the heavy shock or strain incident to the drilling and casing lowering and raising operations, it being a further object to provide a knock-down structure which can be erected or taken down at a minimum expenditure of time and labor.

It is well known that in wood derricks of the compression type, itis desirable to employ elements which two men can safely handle, but heretofore the safety factor necessary in such derricks for deep Well drilling especially, has called for the use of girts which.

it was hazardous for two men to handle, as relatively large timbers were necessary to minimize the twisting movement of the derrick legs and the chance of the securing bolts tearing out of the ends of the girts, as in such derricks heretofore the girts have been fitted in overlapping relation to the legs on the corner brackets connecting superposed leg sections together and in consequence the securing bolts have extended crosswise of the girts near the extremities of the latter and under force tending to expand or contract the derrick, the bolts vibrate and tend eventually to tear out of the ends of the girts. I have found that the weaving of the derrick in high winds and the heavy strain otherwise imposed upon it when drilling or in the raising and lowering of the casing-weighing sometimes several hundred thousand pounds,can be successfully resisted by the use of relatively light girts provided their full length can be utilized to resist compression strain and metal reinforced plates are employed to guard against tearing out of the securing bolts in derrick expansion or spreading strains, it being also desirable for deep well drilling, to furthermore protect the girts against fracture near or at their middle portion, and it is my object specifically, to provide such a construction.

With this object in view this invention consists in certain novel and useful features of construction and combinations of parts as Figure 2 is a horizontal section on the line ll1l of Figure 1.

Figure 3 is an enlarged vertical section on a the line III-IH of Figure 1.

Figure t is an enlarged. horizontal section on the line IVIV of Figure 1.

Figure 5 is a detail perspective view of a girt constructed in accordance with the in-.

vention.

In the said drawing, 1 indicates superposed timbers constituting legs of the derrick, and connecting said legs firmly together at their meeting points are corner brackets, shown in this instance, as composed of an outer right angle member 2 and an inner right angle member 2 clamped rigidly together and upon the posts at their meeting ends, the outer members having arms which in length exceed the width of the respective legs, and said arms are connected by brace rods or the like 3 to the corresponding arms of higher and lower brackets of the same type. The braces are thus crossed braces and through the use of turn-buckles (not shown as old in the art) apply compression strain on the derrick at all four sides thereof. i

In derricks of the type above outlined, girts extend at all four sides between and are connected to the legs or the connecting brackets thereof, but in derricks of this type the girts are usually bolted to the outer sides of the brackets so that practically all strain imposed when conducted by two men, especially the girts which are disposed at .a considerable altitude. 7

I have found that it is possible to efficiently and safely employ relatively light girts which can be easily and safely handled by two men, by disposing the girt-s in endwise abutting relation with opposite legs or the brackets uniting themembers of the legs, provided the ends of the girts where bolted in place are equipped with reinforcing; plates to guard against the tearing out of the bolts under expanding action of the derrick, the collapsing tendency of the derrick being resisted successfully because it applies endwise pressure directly on the girts. It is desirable however, especially for deep well drilling, to reinforce such relatively light girts near their middle, as this guards against breakage of the girts under compression strains applied thereon,

and yet leaves the girts free for resilient action under the weaving or movement of the the bolts 7 with a single tool,

reinforce plates 6 which at their derrick in high winds or when subjected otherwise to heavy strain or shock.

The relatively'light girt referred to, is indicated at 4 and each of such girts is interposed directly between a pair of opposite legs or the brackets connecting the same, and bolted to each girt at each end at 5 are outer edges conform to the angle given to the girts so that they shall bear for the full area of their ends squarely against the upwardly converging legs or the connecting brackets thereof. The girts 4 also bear at their outer sides against and are flatly overlapped by the extended ends of the outer members of the connecting brackets, and are bolted as at 7 to said overlapping ends, it being preferable that the openings of the reinforce plates whichreceive the bolts7, shall be of angular form as at 8, and that a portion of the shanks of the bolts shall be of corresponding formin order that one man may be able to readily tighten up such as an end wrench. i

The bolt connections at '7, under expansive and twisting actions of the derrick are subjected by the outer angle plate 2 to a shearing action, but this expansive or twisting and hence shearing action is minimized by providing the additional bolt connections 5 connected to the bolt connections 7 through the intermediacy of the reinforce plate 6.

A set of girts assembled as explained, guard effectually against the tendency of the legs to rotate or twist more eli'ectually than girts which overlap and arebolted on the outside of the legs as conventional in this type of derrick, besides, as already pointed out, offering proper resistance to collapsing movement of the legs and more safely guarding against the possibility of connecting bolts tearing out of the ends of girts under expandnig or spreading action of the legs. It is desirable in structures of this character to provide for a certain amount of resiliencyin the girts, and to permit this andat the same time guard against danger of breakage, I bolt as at 10 to each girt at its middle, an angle plate 11,

especially if the derrick is to be employed for deepwell drilling where the shocks and strains to which the derrick is subjected are ordinarily much greater than those encountered in relatively shallow wells.

From the above description, it will be apparent that I have produced a structure embodying the features of advantage set forth as desirable in the statement of the object of the invention, and which is susceptible of minor changes without departing from the spirit and scope of the appended claims.

I claim:

1. The combination of an upright composed of two members arranged in superposed endwise abutted relation and of'rectangular cross sectional contour, a pair of rightangle shaped brackets fitting flatwise against diagonally opposite corners and sides of and bridging the joint between said members, the arms of one bracket being engaged with and fastened to the opposing arms of the other bracket, girts abutted sidewise against the arms of the last-mentioned brackets and'endwise against the respective arms of the other bracket, and bolts extending through the gi-rts and the bracket arms in sidewise abutted relation with the girts.

2. The combination of an upright composed of two members arranged in superposed endwise abutted relation and of rectangular cross sectional contour, a' pair of right angle shaped brackets fitting fiatwise against diagonally opposite corners and sides of and bridging the joint between said members, the arms of one bracket being engaged with and fastened to the opposing arms of the other bracket, girts abutted sidewise against the arms of the last-mentioned brackets and endwise against the respective arms of the other bracket, and a bolt extending through the lower upright member and the pair of'brackets.

In witness whereof hereunto affix my signature. CHARLES W; LYNCH. 

